Numerous devices and methods exist for locking a vehicle steering column from movement. Most commonly, such devices and methods prevent the steering column from being rotated to steer the vehicle. The vehicle can be a car, van, truck, motorcycle, bus, or all-terrain vehicle having a number of wheels, a boat with one or more rudders, a snowmobile with skis, a vehicle having one or more tracks, and the like. A steering column lock used in any such vehicle is typically employed to prevent vehicle theft or unauthorized use.
A popular and well-known mechanism for locking a steering column is a lock bolt that is spring-loaded into direct or indirect releasable engagement with the steering column. Such engagement can be by removable insertion of the lock bolt into a groove, a notch, teeth, or an aperture in the steering column or in a gear, plate, or other element connected to the steering column. A mechanism is normally provided for retracting the lock bolt against the spring-loaded force to unlock the steering column for vehicle operation. As is well known to those skilled in the art, the mechanism can retract the lock bolt in response to user insertion and turning of a key or in response to one or more signals from a control system coupled to an actuator driving the mechanism.
Common design concerns with steering column locks include the ability of a lock to reliably lock the steering column and protection against the lock bolt engaging and locking the steering column during vehicle operation. For example, the lock bolt of a steering column lock should be able to properly extend and engage with the steering column (or element connected thereto as described above) even when the steering column is being turned. As another example, a familiar problem with many conventional steering column locks is the ability of a user to turn an inserted ignition key when turning force exists upon steering column from the front wheels of the vehicle. After the lock bolt has been inserted into the groove, notch, teeth, aperture and the like in its extended and locked position, a turning force from the front wheels can bind the lock bolt in this position. Typically, the user must turn the steering wheel to release the binding force upon the lock bolt in order to turn the ignition key, retract the lock bolt, and thereby unlock the steering column.
While lock bolt binding is not necessarily a critical design flaw in conventional manually-actuated steering column locks, it can be much more significant in newer steering column locks that are not mechanically connected to an ignition lock cylinder for actuation thereby. With the introduction in recent years of vehicle security systems in which a steering column lock is locked and unlocked by an electronic controller connected to one or more steering column lock actuators, there is little need to locate a vehicle's ignition control (e.g., switch, button, and the like) adjacent to the steering column lock. The ignition control can be directly or indirectly connected to the steering column lock by wiring alone, and therefore can be located almost anywhere in the vehicle. However, without the ability of a user to mechanically manipulate the lock bolt as in most older steering column lock designs described above, reliable lock bolt disengagement can be a significant problem, particularly when the lock bolt is subjected to binding forces.
Other design concerns with steering column locks include lock complexity and lock manufacturability. Conventional steering column locks typically fail to address these concerns well. By way of example only, many steering column locks are assembled from a relatively large number of parts connected and fastened together in a time-consuming and expensive assembly process. In addition, little concern is normally paid to the complexity of the parts in many conventional steering column locks, thereby significantly increasing the manufacturing costs and end prices of such locks. Lock complexity can also lead to increased potential for lock assembly errors, operational problems and even malfunction.
In light of the problems and limitations of the prior art described above, a need exists for a steering column lock that is relatively simple, is easy and relatively inexpensive to manufacture and assemble, does not require mechanical actuation by a user, can be controlled and operated electronically, reliably locks the steering column even if rotating, and reliably unlocks the steering column even if the lock bolt is subjected to binding forces. Each preferred embodiment of the present invention achieves one or more of these results.